"turbulence is on the rise" Is it?

[PAXboy]

Do the aviators agree with this:
“It is predicted there will be more and more incidents of severe clear-air turbulence, which typically comes out of the blue with no warning, occurring in the near future as climate change takes its effect in the stratosphere,” Dr Paul Williams, a Royal Society research fellow at Reading University, said last week. “There has already been a steady rise in incidents of severe turbulence affecting flights over the past few decades. Globally, turbulence causes dozens of fatalities a year on small private planes and hundreds of injuries to passengers in big jets. And as carbon dioxide levels in the atmosphere keep on rising, so will the numbers of incidents.”Have you experienced an increase in turbulence?

https://www.theguardian.com/world/2016/sep/11/cost-bumpy-flights-air-turbulence-global-warming-united-airlines

[MaverickPrime]

With an increase in the number of people and aircraft flying you could assume that the number of turbulence incidents would, consequently, be directly proportional.

[DaveReidUK]

Do the aviators agree with this:
Have you experienced an increase in turbulence?

I suspect that most pilots' experience of CAT is so infrequent as to make it difficult for an individual to detect a trend, presumably why the research didn't use anecdotal evidemce but aggregated data from many thousands of flights.

With an increase in the number of people and aircraft flying you could assume that the number of turbulence incidents would, consequently, be directly proportional.

Except that the data and modelling shows that to be an incorrect assumption, which is rather the point:

https://www.wmo.int/pages/prog/arep/wwrp/new/wwosc/documents/Williams_CAT.pdf

[underfire]

This 'study' looks more like attempts to get funding for studies by claiming that increased CO2 (ie man made climate change) will cause more CAT.

[FE Hoppy]

I always find posting a random graph is the best answer to "global Warming" scare stories.

Here's one I found that might be relevant.

http://policlimate.com/tropical/global_running_ace.png

[G0ULI]

GPS locked automatic navigation systems mean that aircraft are more likely to fly into the wake turbulence of preceding aircraft on the same track unless positive action is taken to offset each flight track slightly.

More, and heavier aircraft flying around means more opportunity to fly through aircraft created turbulence, not some effect of global warming.

[Genghis the Engineer]

The research is frankly in early days, but I know and work with Paul Williams, and the article is a reasonable explanation of some aspects of his work.

The basic principle is quite simple - increased energy in the atmosphere (global warming / climate change / call it what you will) is particularly causing increased circulation in the atmosphere, and that is putting more energy into the jetstreams.

The north polar jetstream is particularly significant because of its importance in transatlantic flight. There's good evidence that the NPJ is becoming more energetic - this has two impacts: one is that the Rossby Waves (the meanders in the jetstream) are getting wider, another is that the core velocity in the NPJ is greater. This we know.

Because major CAT encounters are particularly associated with the edges of the jetstream, then theoretically this is going to both create more opportunities for CAT encounters (as there will be more intersections of the NPJ) and more severe CAT (because of the greater sheer stresses caused by the greater core velocities).

Anecdotally, this "seems to be" true, but at the moment, the hard evidence is pretty weak. We're working with one major carrier to mine their flight recorder data, and as we go further will probably be more players we talk to as well.

But it would not be true to say that we know a lot yet - we're at the start of a research journey here. Nonetheless, if we are right - it's important, and that's why we're working on it.

There are a load of other effects we're looking at as well - if anybody happened to be at Farnborough Airshow this year, on the Wednesday, you might have heard me give a talk on it.

G

[Uncle Fred]

Good info Genghis. Is there a YouTube video of your talk? I would like to see it if there is.

[Pontius]

Nonetheless, if we are right - it's important, and that's why we're working on it.

So say you but I'll go with the previous suggestion of creating a problem to secure more funding. Let's say you are correct; what then? How does that affect one iota what we do when ploughing the skies? What practical use is there of this study, instead of just more theory bound up in a big book with a clever bloke's name on it?

We could of course, very easily, prove his theory correct. More carbon dioxide = more CAT and more fatalities (allegedly). Therefore, reduce carbon dioxide by reducing the number of those nasty machines in the air that produce the stuff and, hey presto, fewer CAT incidents. Cause and effect or something, isn't it?

The reality is that aircraft numbers are going to increase, not decrease. Whether his theory is correct or not there will be an increase in CAT encounters and, in my opinion, just shows that a study such as his may be alright for white-coated boffins to sit around and discuss but the result of his work will not make any difference to the way we operate.

For lentil-eating, vegan sandal wearers it will be great news as it just gives them another excuse to gob off about how carbon dioxide is now proven to actually kill people because of CAT.

[Derfred]

Or perhaps a not-so-random chart from NASA:

Climate Change: Vital Signs of the Planet: Global Temperature (http://climate.nasa.gov/vital-signs/global-temperature/)

[VH-Cheer Up]

GPS locked automatic navigation systems mean that aircraft are more likely to fly into the wake turbulence of preceding aircraft on the same track unless positive action is taken to offset each flight track slightly.

More, and heavier aircraft flying around means more opportunity to fly through aircraft created turbulence, not some effect of global warming.And RVMS puts aircraft closer together, increasing chance of wake turbulence events.

But isn't this about clear-air turbulence, which is quite different to wake turbulence?

[DaveReidUK]

But isn't this about clear-air turbulence, which is quite different to wake turbulence?

Yes, the latter (in this context) is a complete red herring.

Now that we've finished rubbishing scientists for doing science, who's next ? :O

[HeartyMeatballs]

I would say it's reduced. Years ago strong turbulence over the Pyrenees and Alps used to be standard in summer. Now it's once or twice per season and that's flying over them five days a week.

TS and associated turb is exactly the same as it's always been.

[underfire]

Now that we've finished rubbishing scientists for doing science, who's next

I see quite a bit of 'scientific studies' looking for funding attempts by adding 'as it relates to global warming' or in this case, directly, as CO2 increases (ie man made).

I seem to remember that aviation itself is being blamed for global warming by increasing CO2 levels in the upper atmosphere, creating holes in the ozone, and of course, the warming effects of the condensation trails.

[Nemrytter]

I see quite a bit of 'scientific studies' looking for funding attempts by adding 'as it relates to global warming' or in this case, directly, as CO2 increases (ie man made).Do you have any proof that this is one of them? Perhaps you might like to actually do some research before rubbishing this scientist and his work. Failing to do so is slanderous and, quite frankly, incredibly rude.:=

[DaveReidUK]

I see quite a bit of 'scientific studies' looking for funding attempts

Are you suggesting scientists should work for free? Do you?

[Genghis the Engineer]

Re: the talk. Sorry, so far as I'm aware nobody was recording it. I am likely to be repeating it at the Into the Blue event in Manchester next month, in some form, but haven't had that confirmed yet...

http://www.nerc.ac.uk/latest/events/blue/

Re: funding. Well of course. Scientists, like anybody else, need work coming in to pay the bills. The mechanism for most of them is that they propose research projects and go to funding bodies to make that case - if they are successful, it's because they have passed a review of whether their proposed research is both important, and significant new science. Only fairly minor research projects usually get done without that sort of process in the background, and universities are to a significant extent funded that way.

At the moment what we're doing is early stages and indeed we're exploring the basic issues preparatory to making those grant applications. CAT is actually a relatively small part of the broader topic of the impact climate change *may* be having on aviation. Other, more core, topics, include shifting large bird populations (think birdstrike risk) following their food sources as surface wetness patterns shift, airport ability to manage more regular and severe rainfall events, air traffic management of increased frequency and severity severe weather events (think a big CB over the top of LHR for an hour - where's the capacity to take and park all the big jets in that time?, also ask yourself what happens to all the water?, can you maintain safe IFR separation as everybody else routes around it), all those short single runway airports next to sea and sea level (most of Greece?) as peak surface temperatures increase: prevailing wind vectors shift away from net runway alignment and sea levels rise. The science seems to also say that the speed of sound in the stratosphere has dropped by about 1% in the last 25 years, and we're looking at what that may be doing to long haul cruise groundspeeds (ditto shifting upper winds). For that matter, whilst small beer in the UK, going overseas higher peak surface temperatures raises questions about safety of fuel storage, and the working conditions of ground staff. The long term climate models do suggest changing fog patterns - if the computer models are right (clearly a big question in itself, I am always sceptical of the outputs of the modellers) Edinburgh will see virtually no fog in 25 years, but other places may see more.

It's keeping us all fairly busy - CAT is actually quite low down the priority list of things we're thinking about at the moment, but it does grab headlines and may prove important as we mine the data.

G

[Permafrost_ATPL]

I always love it when people with no background in Climate Science google a random graph, like the one above about cyclones, and declare that they have single handedly defeated the argument of a properly conducted scientific study (by a Royal Society fellow) on CAT - which has nothing to do with cyclones.

FE Hoppy, I also assume that you call studies that show a strong link between cigarettes and smoking "scare stories by people desperate for funding" ? :ugh::ugh::ugh:

[Hotel Tango]

So let's assume the chance of severe CAT on the edges of the NPJ does increase over the coming years. How will it affect aviation? Surely if it becomes that bad it will just be a matter of tracking well clear of the NPJ and accepting slightly longer eastbound crossings. Or am I being too simplistic here :)

[sudden twang]

Yes it's been much worse everywhere over the last 2 years. Perhaps not severe CAT but certainly moderate for more lengthy periods of time.
I may just be unlucky though.

[Basil]

Come up with important research project.
Get large grant.
Do interesting work.
Get paid.

What's not to like? ;)

[ZOOKER]

Ghengis, thanks for the link.......I've just registered to attend at Manch'.
Just an empirical observation, no data to back it up, but when I first set up camp in the Mt. Belzoni area, 34 years ago, thunderstorms were a frequent occurrence. Some of these were large and would often last for ages. Recently, the numbers seem to have declined and this has even been noticed by friends with no real interest in meteorology etc. So far this year, I only remember hearing thunder about two times. Could this be due to more vigorous circulation over The U.K., therefore not allowing so much Cb formation as in previous decades?

[Noxegon]

I suspect it's on the rise, and fall, and rise, and fall, and so on...

I'll get my coat.

[G0ULI]

The very existance of the northern and southern jet streams was unknown until the Second World War. Exploiting them to speed up journey times is an even more recent trend.

We have very little data to assume that the default circulation of the jet streams has been smooth and laminar for eons although historical and physical evidence of climate around the world can be used to infer the track of the jet streams. It may well be that the last fifty years represent a particularly calm period and the jet streams are reverting to more normal circulation.

Alternatively it may be that the many aircraft exploiting the jet stream core are responsible for upsetting the balance of this phenomenon and actually increasing the turbulence of the air flow, as pointed out by other posters.

So this could be an effect of climate change, or an effect of aircraft effectively robbing some of the energy from and disrupting the smooth flow of the jet streams.

Wind farms are known to disrupt local weather patterns, so why shouldn't the presence of hundreds, if not thousands, of wide bodied jets not have a measurable effect? Why is anyone surprised that the aircraft themselves might be responsible?

There are always energy costs associated with moving things from one place to another. If you extract energy from the wind to reduce fuel costs, that energy is lost to the natural weather system and absorbed by the aircraft in order to increase its ground speed. Several thousand aircraft a day, all individually absorbing a little energy, soon adds up to a lot.

I maintain that the accuracy of GPS navigation systems tends to ensure that aircraft all track along very similar courses which can further concentrate the disruption to the normal jet stream flow and the possibility of wake turbulence in otherwise clear air.

I do appreciate there is a difference between CAT and wake turbulence, but the subtleties are probably lost on the passengers in the back when their drinks go flying.

Is there a correlation between a general increase in global temeratures and the average height at which commercial jets fly. In the 1960s 30,000 feet was considered high. Jets are regularly flying at heights in excess of 40,000 feet today. It seems to me that the increase in global temeratures has pretty much tracked the height of the average flight over the Atlantic (and elsewhere) as it has increased. Just how much did Concorde contribute to atmospheric change? There does appear to have been a slight dip or slowing in temerature rise since it stopped flying. There are such a huge number of variables, it will be very difficult to prove the case one way or another for perhaps several decades to come.

So a good project to seek funding for, even if the results may be a long time coming and somewhat inconclusive in ways to mitigate the effect, apart from avoiding flying in the jet stream.

[Junkflyer]

The statement that there are about 40 deaths annually in the US due to turbulence is not even close to being true.

[Genghis the Engineer]

The very existance of the northern and southern jet streams was unknown until the Second World War. Exploiting them to speed up journey times is an even more recent trend.

Being extremely picky, actually just before. The first paper explaining the existence of the NPJ was published in 1940.

Here it is (http://empslocal.ex.ac.uk/people/staff/gv219/classics.d/Rossby-planflowQJ40.pdf)

Gann, in his book "Fate is the Hunter" talks about the first exploratory use of jetstreams by air transport pilots during WW2.

The possibility that some modification is caused by aircraft flying in those regions is certainly there. I suspect more due to high tropospheric / low stratospheric emissions, rather than direct movement of air, but I may be wrong in that regard and I don't think that anybody has looked hard at the question.


In the case of our research however, we're *not* thinking much about the impact of aircraft operations on climate change - other people are doing that. We're thinking about the impact of climate change on aircraft operations: a linked, but somewhat different question.

G

[Loose rivets]

I would say it's reduced. Years ago strong turbulence over the Pyrenees and Alps used to be standard in summer.

I concur. It seemed standard ops to wear shoulder harness a couple of times a week when near the Alps.

One night we moved over because the core of a CB could be seen on the radar, and visually under layered cloud some 5k' below. We were 10 miles east in clear air when we dropped the first thousand feet, not once, but three times. It was like dropping down concrete steps. One of them, my jacket lifted up on its hanger indicating a tad of negative g.

I'm living on memories now but one vivid one was of the training staff of Eagle's 1-11 fleet suddenly encountering CAT in an airway over France. They looked at each other, shut the taps and fell out of the sky with the airbrakes out. All four of us had simply never experienced CAT before, and it was moderate at the most, though that little aircraft was particularly twangy.

One last thing. The Ozone layer is bewilderingly thin - the most whispy membrane protecting our planet.

[Cazalet33]

Convective turbulence may be on the up.

On the other hand ....

[Basil]

Convective turbulence may be on the up.

On the other hand ....
Hah! Made me smile.

[safetypee]

Crews are more turbulence aware due to an increasing litigious culture; greater attention to seat belts, etc.
Modern aircraft are more flexible, even with flight guidance Turb modes.
Higher cruise speeds; modern aircraft have higher rough air speeds - a structural requirement not necessarily for passenger comfort.
More flights, greater route variety, greater exposure to existing levels of turbulence.

... a bit more room on the post card.

It's better to believe in global warming than not ... after Pascal.

[DaveReidUK]

The statement that there are about 40 deaths annually in the US due to turbulence is not even close to being true.

Fifteen years ago, the US was averaging about 25 turbulence-related fatalities per year (almost all GA rather than air carrier, obviously), so not entirely out of the ballpark.

[IcePack]

Before I retired. I noted my outfit used to plan us in the core on a regular bases. Often smooth but occasionally as rough as guts. Not nice. So is it getting worse probably not but new systems looking for the quickest flight time makes it seem so.

[PAXboy]

My thanks to Nemrytter but particularly to Genghis for giving us 'the horses mouth'. :ok:

Now, I would like to get the thread back to the question I asked: Do commercial airline flight crew, think that turbulence is getting worse?

If you want to talk about climate change and if the govt should fund the training of Badgers not to cross active runways, please don't bother. :rolleyes:

[FlightlessParrot]

Certainly, people do put in references to the flavour-of-the-month to increase funding opportunities: as for example, all those studies of every type of illness which included, at the end, a positive correlation with tobacco use. But this does not invalidate the fact that tobacco smoking is a deadly habit, and that the tobacco companies deliberately lied for many years to protect their profits.

The claim that AGW is just a ploy by scientists to get grants is a good example of the big lie. A million bucks is a major grant, even in science; I would assume it's pretty much the year's lunch budget for the PR department of a big coal company. Big coal, especially, is denigrating careful science to protect its profits, and for some strange reason a lot of people accept their obvious lies as though they were the truth. I do not understand why; you would not expect magical thinking and hostility to science in an aviation community, so it must be some kind of personal anxiety.

This is of critical importance to the aviation business, since there is no visible alternative to fossil fuels for aviation; it is therefore necessary that the aviation community should support the reduction of carbon emissions in all areas where there are alternatives.

Genghis produces a careful account of the research, clearly in the initial, exploratory stages; Genghis is well known for knowledge of aviation matters, but because he accepts the overwhelming science on AGW, some people think they have the right to impune not only his knowledge, but his motives. I very much fear that Trump will win the election, as wilfull ignorance seems to be the way of the future.

[Nemrytter]

To those complaining that this research was some kind of scam to get more funding: Have you actually looked at who funded this research and what the funding was for? His funding comes from a grant to improve climate models and reduce errors, nothing directly related to aviation.

I'd also suggest that you read the original paper before you rubbish the research, y'know - so you actually know what you're talking about. The paper is available here (http://www.met.reading.ac.uk/~williams/publications/nclimate1866.pdf).
Maybe now we could get back to thinking if any of us think that the CAT encounter frequency has increased in recent years.:ugh:

[G0ULI]

Correct me if I'm wrong, but the paper published three years ago unequivocally states that CAT incidents have increased and are likely to continue do so based on data gathered. The mesh grid used is too coarse to provide specific predictions for individual aircraft, but that is to be expected.

Given that the gross details are already mapped and conclusions drawn, it seems that the best way forward would be to equip as many aircraft as possible transiting these routes with calibrated accelerometers which broadcast the data back to collection point(s). That way you could get a precise GPS position and altitude linked to an objective measurement of the turbulence experienced.

Such data could then be overlaid on the existing mesh calculations to verify their accuracy and improve predictions. New sources of data are needed rather than simply rehashing existing data sets at finer scales.

[Mr Mac]

PAXboy
I am not a pilot or aircrew but a very regular SLF (perhaps too regular) and have been flying extensively on Business since 1980,s and before that on flights back to school and holidays from the early 60,s. As my returns to school involved flight to the UK from Chile we are not talking short hops. In my I agree limited experience compared with aircrew, I on the hole seem to endure less issues with CAT then we did back in the 60,and 70,s. I speak as one who had the joys of a famous AF CAT incident so it may colour my judgment but I am still flying 200,000 miles per on average(last years total 197843) so I do have a reasonable amount of flight time to judge by. Would be interested to here from other SLF thoughts.


Regards
Mr Mac

[DaveReidUK]

I speak as one who had the joys of a famous AF CAT incident so it may colour my judgment

AF006, presumably?

Scary stuff, with 3 F/As concussed.

[ZOOKER]

I wonder whether the introduction of RVSM could be a factor in the perceived increase or decrease of CAT encounters?

[Yamagata ken]

Ghengis the ''Engineer'' is using climate model output as data for a modelling exercise. Feed climate model results into another model and looky here: we have another grant. Trebles all around.

Sorry to rain on your lucrative professionally rewarding ''Engineer'' parade, but model outputs aren't data.

The FAA give this fact sheet (data, not model output) Fact Sheet ? Turbulence (http://www.faa.gov/news/fact_sheets/news_story.cfm?newsId=20074)

A decline in injuries from 107 in 2009 to 21 in 2015 (actual data, not model output). My model clearly demonstrates that the Catastrophic Global Warming (which is not happening) is reducing the incidence of CAT. (I'm being selective here, but one of the great things about climate ''science'' is you can pick your data to support your position).

[Hotel Tango]

I wonder whether the introduction of RVSM could be a factor in the perceived increase or decrease of CAT encounters?

I very much doubt it!

BTW OP, speaking strictly as a passenger, I personally have experienced less turbulence on the NATs the past decade in contrast to previous decades. Then again, I may just have been lucky and have now put the kaibosh on future smooth rides :eek::)

[neila83]

It's fascinating how many pilots find the time to qualify themselves as experts in climate science, to the extent they feel justified in rubbishing work by qualified scientists of years training, PhDs etc etc.

These same pilots are the first to criticise anyone without a pilots background for commenting on flight matters, quite rightly in most cases.

I wouldn't trust a climate scientist to fly a plane, maybe you should take your own advice and let them do your job, and you do yours.

Ironically of course, the same people who deny man made climate change will often use the evidence that the earth has warmed and cooled naturally in the past, as if that somehow prevents the possiblity of non natural causes now, which is a logical fallacy. Of course this evidence is provided by the same scientists who produced the evidence for man made climate change, the deniers just pick and chooose which science they believe.

[Genghis the Engineer]

Ghengis the ''Engineer'' is using climate model output as data for a modelling exercise. Feed climate model results into another model and looky here: we have another grant. Trebles all around.

Sorry to rain on your lucrative professionally rewarding ''Engineer'' parade, but model outputs aren't data.

You obviously feel that calling myself an "engineer" is offensive in some way - well I am a chartered Engineer and Fellow of the Institution of Mechanical Engineers, but if you prefer "pilot" (CPL, 1600 hours, various ratings) or "Scientist" (PhD, 20+ papers in scientific journals, several courses in atmospheric science) you're most welcome. Although, if you'd caught my grandmother in a good mood with a quip like that, I think she'd have just pointed out that the person who first resorts to name calling has just admitted they've lost the argument. More normally, she'd have used much stronger words than that.

I'm not really Genghis the "modeller" - the last computer model I wrote was years ago to model the behaviour of the Jaguar after pickling in a steep dive in ISA++ conditions; validating it from the back seat of a T2 was fun. I work however with people who do modelling very well, my skills are elsewhere, mostly in helping them obtain real world data to validate those models.

But you are quite right that models are only models - but they're also something the entire world relies upon nowadays. Financial models, weather forecasting models, aircraft performance models, medical research drug response models.... Personally I'm mostly working with data, good old fashioned equations, and professional knowledge. And working with some hellishly clever scientists and aviation professionals across several countries.

If you actually bothered to read what I'd posted, you'd also see that I said that CAT data is very weak, and relatively fringe to what we're studying. It happens that a newspaper found it interesting to pick up and print, and a major carrier is interested enough to let us data mine 4 million hours of FDR data to try and make some sense of the question.

Care to tell us your own scientific qualifications, as you're doubting other peoples'?

You could also perhaps explain why you disapprove of the process of (1) establish basic track record, (2) create research proposal, (3) competitively use proposal to apply for research grant, (4) do research if you got funded, is wrong in some way? It is the way most of the western world manages and commissions scientific research, and unsurprisingly, different funders have their own various priorities they use in allocating funds - which for some funders includes anthropogenic climate change (I don't like the term "global warming" as it's too simplistic, ditto the obsession with CO2 to the disregard of all of the other factors.)

G

[Mr Mac]

DaveReidUK
Out by two digits. AF004 Boeing 707 Nebraska carried onto Paris (should have put down)where we were greeted by fleet of ambulances. My last AF flight, and that of my Father to. Long time ago, but can honestly say I think we had worse on trips up from South America, but not so many people /carts moving around so not so dramatic. Also BCAL would have put down I am sure. AF captain apparently went onto fly Concorde so his decision making must have been judged to be correct.
Cheers
Mr Mac

[langleybaston]

QUOTE:

Because major CAT encounters are particularly associated with the edges of the jetstream, then theoretically this is going to both create more opportunities for CAT encounters (as there will be more intersections of the NPJ) and more severe CAT (because of the greater sheer stresses caused by the greater core velocities).

I am/ was a meteorologist as opposed to a climate scientist. I do not know what an "intersection" is in the above context.

What I do know is that the argument assumes that, whereas jetstreams will increase increase in velocity, the surroundings [above, below, left, right] will not.

Otherwise the sheers will not, may not, increase.

Is there a fallacy here?

[Genghis the Engineer]

The important factor is the difference in velocity vectors, rather than the scalar velocity.

There are indications that the velocity vectors are shifting, that's what Paul Williams recent papers have been about. They've not necessarily been aligning themselves with the NPJ. Without running through the maths (as I don't think I could on my own) intuitively some vectors will be closer to the NPJ, most will be more different.

G

[steamchicken]

So many people in this thread don't seem to have had the idea you can correct for more flights by *dividing CAT encounters by number of flights, or mileage, or pax-miles, or ton-miles*. It is to laugh.

[DaveReidUK]

Dividing CAT encounters by RPMs would indeed be a pretty meaningless statistic.

[AnotherRedWineThanks]

A model is a simulation. Should we ditch flight simulators completely, or continue to use them while taking account of their known limitations?

[langleybaston]

Wind in general, and jet streams in particular, are ultimately driven by temperature contrast [and of course modified by earth rotation].

I have no idea if jet streams are becoming faster: the period of accurate measurement is too brief to be very informative [only Aireps or whatever, many and often, give enough data, and then only on busy routes].

If they are becoming faster, surely the circulations outside the cores will also be faster, as part of the global mechanism for distributing the unequal heating of the planet polewards.

This being so, I cannot see why sheers [contrasts] of wind vector might be increasing.

And I still don't know what these "intersections" are.

[G0ULI]

langleybastion

Try replacing "intersections" with "interactions" and the meaning will become clearer. That it what I took it to mean.

On the subject of whether pilots are truly qualified to question or comment on the work of profession climatologists and weather experts, I believe they are. Pilots, mariners and farmers all interact daily with the weather in ways that affect their personal survival and livelyhood. They may not have the maths and figures to back it up, but personal experience and living to a ripe old age must count for something.

[no sig]

Surely, it shouldn't be too difficult to answer the question, 'are north Atlantic Jetstream velocities on the increase? We should have at least of 50 years of upper air data, not to mention real time NAT position reports with wind/temps to research. But over a 46 years career in airline ops and flight planning, I look at the upper charts these day an do think that Jetstream velocities are in the increase, or at least the incidence of very strong Jetstream are.

[Derfred]

On the subject of whether pilots are truly qualified to question or comment on the work of profession climatologists and weather experts

Weather experts, yes I would agree.

Climatologists, no. That requires numbers, and lots of them. Anecdotal evidence counts for nought in the climate change discussion.

[Empty Cruise]

And another random graph for those that still doubt we are, ahem, having intercourse with the climate...

http://imgs.xkcd.com/comics/earth_temperature_timeline.png

[Ian W]

Weather experts, yes I would agree.

Climatologists, no. That requires numbers, and lots of them. Anecdotal evidence counts for nought in the climate change discussion.
Correct.
A change in climate is said to be a change that is noted over a 30 year period. Changes from one year to the next or even one decade to the next are weather not climate.

[langleybaston]

That buggers weather prediction for ever, then!

[Genghis the Engineer]

The definition of "climate" is "average weather"

Very hard to know what that is without a lot of observations and a lot of maths. And that over a long period of time to say if it's changing or not.

G