Weather! deterministic or chaotic system?

[symesie04]

I was reading with interest an earlier thread whereby the nature of deterministic and chaotic systems was being argued. At the same time i was listening to the radio where they were discussing why the jet stream had shifted leading to the floods in areas of northern england. A expert was basically saying that it is a recognised pattern every 15 years or so. Relating the two inputs made me wonder of the systems the weather would be classed as considering that deterministic systems can be unpredictable and chaotic systems can be predicted. I wonder if the weather can ever be given a pre determined prediction given that we can never know the starting state of of any weather system. This would be due partly due to the very unpredictable nature of quantum physics in itslef and also we can never know the exact starting point of any given weather system. Throw into that what seems an (dare i say) infinate complexity of external forces and you would assume that you have a system that would on paper appear totally chaotic. However as afforementioned I have since learned that chaotic systems can be determined and determinstic systems can be unpredictable. So which would apply to weather systems?

As a side note do you think we will ever be able to totally accurate predictions of weather (long term or shot) even with advances in technology?

[starfuel]

I think it was the French mathematiciann Laplace who once suggested that if we knew the initial positions of all the particles we could , in principle, predict the future of the universe using Newtonian mechanics. Unfortunately ( or maybe not! ) Quantum Mechanics later showed that it was impossible even in principle to have this required knowledge. The universe cannot, therefore, be deterministic in the Laplacian sense. Having said that it is obvious that an extremely good approximation is made in many cases, space travel being an excellent example. The more that knowledge of weather systems and associated forces is refined then the more accurate forecasting will become.

Having said all that I know with absolute certainty that if I organise a barbeque next weekend it will rain ceaselessly all day.

Chris

[Phil Fargaze]

Is it right to say that there can be some limits defined to the chaotic or deterministic systems. For example, we can be very sure that it would not snow in August in the south England and that Christmas Day would not normally be 38 degrees centigrade. I can only think that those limits can be set by statistics from previous weather observations, but recently it appears that records are being broken, so it seems that the proverbial `goal posts` are being moved. Does the fact that they are being `moved` suggest a chaotic system.

Sorry if I am barking up the wrong tree.

[Saleratus]

Doesn't it seem obvious that it's deterministic? Someone up there is obviously [removed word] off with us.

[FraserClarke]

recently it appears that records are being broken, so it seems that the proverbial `goal posts` are being moved. Does the fact that they are being `moved` suggest a chaotic system.

No, that's just what you expect from normal statistics. If you have a mean value with a distribution about it (e.g. the amount of rainfall in June), the more samples you take (i.e. the more Junes you have) the better you sample distribution, so the more likely you are to see the outliers from the mean (i.e. set new records).

I think you're right about having to define the timescales. The weather is pretty deterministic on timescales of 0-3 days, and >3 months; between those, it probably tends to be more chaotic.

[Ronnie67]

a new test for determining whether a given deterministic dynamical system is chaotic or non–chaotic. In contrast to the usual method of computing the maximal Lyapunov exponent, our method is applied directly to the time–series data and does not require phase–space reconstruction. Moreover, the dimension of the dynamical system and the form of the underlying equations are irrelevant. The input is the time–series data and the output is 0 or 1, depending on whether the dynamics is non–chaotic or chaotic

[Ronnie67]

check this link out http://www.elmer.unibas.ch/pendulum/chaos.htm

[Alastair Rae]

I won't get into the mathematics/semantics of chaotic vs deterministic but I guess there is too much data involved for it to be practically deterministic. Interesting contradiction is that from 1979 to 2001, the Northern Hemisphere's jet stream moved northward on average at a rate of about 1.25 miles a year yet for the past few summers it's been passing south of Britain rather than north.

[ollypenrice]

James Gleick's book on Chaos attributes much of modern chaos theory to an accidental discovery by a climatologist (Lorenz) that a vanishingly small alteration of initial conditions radically changes climatic outcomes.

And, well... that's me done: I'm just an astrophotographer!

Olly

[DarkStar7]

I made a mistake on the locked thread by confusing the meaning of the words unpredictability with indeterminism. I thought they amounted to the same thing.

Still, if I invited you guys to a BBQ in Sept here in England and told you that it's ok It'll be hot and sunny, I checked it using a Lyapunov Equation.. Could I convince you that the weather would be great?

[DarkStar7]

Determinism I believe is meant in the Scientific community to mean that cause and effect. Fine, but like anything there is a limit and the although the maths equations can dig deeper and deeper our ability to process the information will become impossible. No matter if we had a Quantum Supercomputer working for 24hours, if the weather is in a highly dynamic state ie thundery then predicting where rain will fall after a week with any accuracy would be impossible.

I personally think that when a boson turns into a fermion a tiny singularity forms in the centre of similar to how a twister forms in a storm cloud. As space-time curves into the forth 'spatial' dimension we get mass.Understanding the dynamics of phenomena of any singularity with high degree of accuracy (including a twister)is impossible. This why I predict in the other thread that on July 4th the discovery of the Higgs will remain tantalisingly close nearly there.. but they won't ever find it, it will be inconclusive. There may even be a Higgs detection in one piece of equipment but it won't be conclusively proved by all of the devices.They'll say they need more time and computing power.

My prediction is that more and more unwanted signals in the measurement will never make the discovery conclusive. The signal around 125GeV I predict will resemble the eye of a hurricane, messy around a edges and calm in the centre. They'll be left scratching there heads saying where is it!

I will be very humbled if I'm proved wrong.

[sologuitarist61]

Like a great many things, the weather is both chaotic and deterministic, showing chaotic patterns in the short term, but more deterministic patterns over longer periods.

[symesie04]

Thanks for the responses gents, interesting. So we have established that the weather is either a deterministic or a chaotic system or possible a bit of both. Glad we have cleared that up

[sologuitarist61]

Thanks for the responses gents, interesting. So we have established that the weather is either a deterministic or a chaotic system or possible a bit of both. Glad we have cleared that up

What? You wanted a definitive answer?? :grin:

[ronin]

The weather is neither deterministic or chaotic, it is Problematic. :rolleyes:

[sologuitarist61]

The weather is neither deterministic or chaotic, it is Problematic. :rolleyes:

How true!!!!

[Thirdway]

Weather is a super dynamic system. It's neither deterministic or chaotic. In other words an input will never produce an exact output, but there are recognisable patterns of behaviour within the network. Yes, I did say behaviour. It's living, or rather it's a product of a living system. Even on lifeless worlds this is true. Everything affects everything else. It's balance. Sometimes the balance gets upset and there is a swing as everything settles out. Some swings are unimaginably large and some too subtle to measure.

It has exactly the same behaviour as seen in people. Poke a person with a stick and some will shout and some will strike back. So there is some predictability in that a great enough input will eventually lead to a reaction. We see it in the economy at the moment. Large networks produce regular patterns but although the patterns can often be interpreted they are never certain. At any moment the planet could begin the return to an ice age.

Chaos theory always results in total unpredictability. With Chaos theory the constant lack of predictable patterning would have meant the Universe could not have formed or life to have existed. Deterministic theory would not have allowed enough latitude for the Universe to form, it would have remained in a quiescent state. Chaos theorists would believe that everything is random and so life is just one of those random events. Entropy reminds us that this isn't quite true. Broken cups don't remake themselves when broken.

There is a direct connection between Super Dynamic systems and conscious life.

[sologuitarist61]

We see it in the economy at the moment. Large networks produce regular patterns but although the patterns can often be interpreted they are never certain. At any moment the planet could begin the return to an ice age.

My word that's some jump - from the economy to an ice age in just 39 words!!! (joking)

Weather is a super dynamic system. It's neither deterministic or chaotic. In other words an input will never produce an exact output, but there are recognisable patterns of behaviour within the network. Yes, I did say behaviour. It's living, or rather it's a product of a living system. Even on lifeless worlds this is true. Everything affects everything else. It's balance. Sometimes the balance gets upset and there is a swing as everything settles out. Some swings are unimaginably large and some too subtle to measure.

Absolutely, cause and effect works regardless of where the cause is. A prime example of this is the old chestnut that goes something along the lines of 'A butterfly flapping it's wings in the south Pacific can cause a hurricane in the north Atlantic'.

The problem with the weather in the main is that the causes are never clear. Granted the summer we are having is because the jet stream is not in its usual position and sending all the bad weather our way, but why has the jet stream moved? They are having some very hot weather in the USA at the moment, but is that the cause of the jet stream moving, or yet another effect? There are so many variables it will always be a problematic, it is difficult enough trying to work back why we are having the weather we are, so you can see how difficult it must be to try and actually forecast what is going to happen. At best it will be very generalised, as in 'there is a probability of rain today' - all that means is you could have a dry day whilst someone else gets all the cruddy weather, but who actually gets it and who doesn't is still in the lap of the gods.

[sologuitarist61]

There is a direct connection between Super Dynamic systems and conscious life.

I am sorry but I cannot buy that one. There are Super Dynamic system all over the universe but they have nothing to do with conscious life, unless your meaning is that we are here to witness them.

[Thirdway]

I am sorry but I cannot buy that one. There are Super Dynamic system all over the universe but they have nothing to do with conscious life, unless your meaning is that we are here to witness them.

Far more than that. I know this another way, but a good start is Bells Theorem. No rational thinking is actually wrong, it's just flawed precept based on limited information.

A good analogy is that if you had no concept of a spherical object and believed the world to be two dimensional then you would draw the wrong inference. However, it wouldn't be entirely wrong, because in two dimensional theory it would be a workable theorem.

If you believed the two dimensional concept and were stood on the Earth. Then maybe to test out a theory you would decide to walk in a straight line for as far as you could. After some time you would encounter the same place you had previously set off from. You could continue to run that experiment until you might begin to think there were simply an infinite number of parallel points. You then would return to your original point by retracing your steps. Then you might set off at 90 degrees to your original path and discover more points of similarity. You can either believe that there are infinite identical points on a flat surface or you make a leap and infer a sphere. That is something that you haven't seen before and cannot draw or model, that leap is necessary to make the connection between conscious life and the rest of the universe as it is currently evaluated. It's not an easy leap to make because, just like the sphere, it cannot be known directly, only inferred.

It's rather like trying to unravel a knot only to discover you are actually the string. There is enough objective evidence to support it just by looking at the original quantum slit experiment and the observer effect. There is enough evidence to show that despite weather showing patterning, it also appears random. That snowflakes are all snowflakes but all uniquely different. That light is both wave and particle at the same time. It's enough to point the way to the existence of something which cannot be drawn or modelled but can only be inferred. The Higgs particle is exactly that type of inference, we can only view it through the mass it creates because once the mass is created the particle apparently vanishes.

God really is in the detail. Life is in the detail.

[sologuitarist61]

It's rather like trying to unravel a knot only to discover you are actually the string.

God really is in the detail. Life is in the detail.

't's rather like trying to unravel a knot only to discover you are actually the string.' What a great thought, I like that one.

Not so sure about the God being in the detail though - unless it is used as a figure of speech - it always worries me when religion is brought into science.

[Thirdway]

't's rather like trying to unravel a knot only to discover you are actually the string.' What a great thought, I like that one.

Not so sure about the God being in the detail though - unless it is used as a figure of speech - it always worries me when religion is brought into science.

That's why I added that life is in the detail. You can add what you like once you realise you are the string. This isn't a discussion on religion and the word religion denotes a certain context of beliefs. That is very close to the inferred sphere, but ( being very careful how I say this ) it also has flawed ideals, not wrong, but flawed. Eventually religion and science will be seen as they are, two sides of the same thing. Both a working towards an idea, religion has gone off on an agenda and science has largely stuck to a plan. Religion will soon realise that it owes its existence to science and science will realise it cannot conceptualise without religions more pure form ( stripped of its mantle it's a very light thing, but weighed down with expectation, morality and ritual it has become leaden ).

Einstein knew this when he said " science without religion is lame, religion without science is blind " ( I think he got that the wrong way around but that's only how I see it ) . There's a great article here that shows more detail behind those words. It's very short.

http://www.guardian.co.uk/science/2008/may/12/peopleinscience.religion

[sologuitarist61]

That's why I added that life is in the detail. You can add what you like once you realise you are the string. This isn't a discussion on religion and the word religion denotes a certain context of beliefs. That is very close to the inferred sphere, but ( being very careful how I say this ) it also has flawed ideals, not wrong, but flawed. Eventually religion and science will be seen as they are, two sides of the same thing. Both a working towards an idea, religion has gone off on an agenda and science has largely stuck to a plan. Religion will soon realise that it owes its existence to science and science will realise it cannot conceptualise without religions more pure form ( stripped of its mantle it's a very light thing, but weighed down with expectation, morality and ritual it has become leaden ).

Einstein knew this when he said " science without religion is lame, religion without science is blind " ( I think he got that the wrong way around but that's only how I see it ) . There's a great article here that shows more detail behind those words. It's very short.

http://www.guardian....cience.religion

I'm afraid we will have to beg to differ on that. One is a belief system that can never be proved ot disproved, the other is a system that can at least be tested, though it might well be wrong the people involved will admit to the fact, wheras those from a belief system have no option but to believe regardless of the evidence.

Still, we are off topic here, so before the Mods steo in, regardless of whether it is or isn't derterministic, it has surely rained down here with almost 2" before breafast.

[cantab]

Relating the two inputs made me wonder of the systems the weather would be classed as considering that deterministic systems can be unpredictable

This was the whole point of chaos theory in the first place - that a simple and entirely deterministic system can produce complex, seemingly random, chaotic behaviour.

I made a mistake on the locked thread by confusing the meaning of the words unpredictability with indeterminism. I thought they amounted to the same thing.

This, again, is exactly what was thought, before the early researchers in chaos theory realised things weren't that simple.

Chaos theory always results in total unpredictability.

No. Unpredictability, but not totally so. The short term behaviour of a chaotic system can be predicted, before small errors in initial conditions get amplified too much. Aspects of the long term behaviour can also be predicted; the exact state is unpredictable, but limits can be drawn. On Christmas day in London it might be -10 degrees C, might be zero, might be +10 degrees. But it certainly won't be minus a hundred or plus a hundred, barring a huge external factor like an alien invasion or a nuke going off.

[Thirdway]

I'm afraid we will have to beg to differ on that. One is a belief system that can never be proved ot disproved, the other is a system that can at least be tested, though it might well be wrong the people involved will admit to the fact, wheras those from a belief system have no option but to believe regardless of the evidence.

:-) scepticism is a great guide.