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

What's not to like? ;)

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?

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

I'll get my coat.

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.

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

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

Here it is

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

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.

Convective turbulence may be on the up.

On the other hand ....

Hah! Made me smile.

Turbulence is on the increase, or not.
 

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.

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.

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.

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:

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.

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.
Maybe now we could get back to thinking if any of us think that the CAT encounter frequency has increased in recent years.:ugh:

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.

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

AF006, presumably?

Scary stuff, with 3 F/As concussed.

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

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

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).