"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/20...nited-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]

Originally Posted by PAXboy

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.

Originally Posted by 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.

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/...lliams_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.

[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

[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]

Originally Posted by VH-Cheer Up

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 ?

[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]

Originally Posted by underfire

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" ?

[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.