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Is Clear Air Turbulence becoming more common?
- aaron695 2y ago[dead]
- oron 2y agoEmployee of SkyPath here. We are trying to give a solution to this problem dedicated thread here : https://news.ycombinator.com/item?id=40828180 https://news.ycombinator.com/item?id=40828180
- bozhark 2y ago3 comments on the same thread. Stop advertising mate Two top level. You suck
- cassepipe 2y ago"Are Clear Air Turbulence events happening more often? In a word, yes. Recent studies have shown a significant increase in the frequency and intensity of CAT conditions over the past few decades. This increase is linked to several factors, most notably climate change." We've had this invisible hand of the market to regulate ourselves. Now we have the invisible hand of the planet. It won't be a fun ride either.
- thiel 2y ago> The Prosser report outlines one of the primary reasons for the increase in CAT events as the intensification of the jet streams, driven by the warming of the planet. As global temperatures rise, the temperature gradients between the equator and the poles become more pronounced, strengthening the jet streams and increasing the likelihood of turbulence . I was under the impression that, as the poles are MORE affected by global warming, the jet stream is becoming weaker? is that incorrect?
- badcppdev 2y agoGot some references?
- mcmcmc 2y agoThey are cited in TFA https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2023GL103814 https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/202...
- the_sleaze_ 2y agoYou might be thinking of the Gulf Stream, which is an oceanic current and definitively weakening, rather than the jet stream, which is an air current.
- quakeguy 2y agoExactly, air currents are becoming stronger with warmer conditions, but the gulfstream being a water current it is expected to become weaker.
- rob74 2y agoTo muddle things even further, there is a (jet) aircraft manufacturer called Gulfstream (https://en.wikipedia.org/wiki/Gulfstream_Aerospace https://en.wikipedia.org/wiki/Gulfstream_Aerospace). ...but I fully agree with the rest of your comment.
- buildsjets 2y agoNot all Gulfstream aircraft are jets. Mine certainly isn’t. Piston powered, burns avgas, spins a propeller, goes around 130 knots.
- HPsquared 2y agoThe jet stream is also driven by temperature differences. Same with most wind and weather, it's all various forms of heat engine. (Edit: though apparently the additional moisture in the Tropics more than counteracts any reduction in temperature difference: see link in Retric's comment)
- wongarsu 2y agoThe jet stream is getting stronger (and its path becomes more erratic), but the reasoning provided in the article is simplified to the point of being wrong. The projected warming at the North Pole is much stronger than the projected warming at the equator, decreasing the temperature gradient. However the moisture carrying capacity of air increases exponentially with temperature. Since the equator starts warmer, a given change in temperature has a bigger effect on moisture carrying capacity. It turns out that heating up the equator by one degree Celsius and the North Pole by 2 degrees Celsius increases the moisture capacity gradient, despite the temperature gradient dropping. And that increasing moisture capacity gradient strengthens the jet stream. (at least that's the intuitive reason they were probably going for. In reality there are many factors and a good bit of "if we simulate it this keeps happening")
- konschubert 2y agoThat’s also what I read: The poles warm FASTER than the equator. Thus, the global temperature gradients are getting smaller. And as a result, not only does the Jetstream weaken: as a result, weather patterns become more stable which leads to greater continuous periods of draught or flooding.
- coldtea 2y agojetstream != gulf stream
- HPsquared 2y agoJet stream is also driven by temperature differences, like basically all weather. Heat engines.
- Retric 2y agoIt’s a heat engine but more than just temperature changes are occurring. “The new study, by University of Chicago Professor Tiffany Shaw and NSF NCAR scientist Osamu Miyawaki, uses climate models to show that climate change intensifies this density contrast because moisture levels for air above the tropics will increase more than above the poles.” https://news.ucar.edu/132935/jet-stream-winds-will-accelerate-warming-climate#:~:text=The%20study%2C%20in%20Nature%20Climate,faster%20than%20the%20average%20wind https://news.ucar.edu/132935/jet-stream-winds-will-accelerat....
- polar_low 2y agoThat is correct, as a longer term trend at least while paradoxically, we are also seeing periods of record strength in the Jet Streams. The truth is there are many oscillations and teleconnections(themselves being impacted by global warming) which influences this temperature gradient on a local/seasonal basis. QBO, El Nino/La Nina and mountain torque events to name a few can move and shift heat at the tropopause in a short period of time and is why we see this wider variance at both ends of the spectrum.
- photochemsyn 2y agoI think the seasonality of the polar environment is a critical factor - while warming is expect to decrease the average equator-to-pole temperature gradient (as all models predict faster polar warming than equatorial warming by a large margin), winter is still winter as the polar axis is tilted, so steep atmospheric gradients are expected over that seasonal period.
- nytesky 2y agoI wonder if this is like an immune system response by mother nature, it’s attacking the thing that’s warming it up i.e. air travel? Self correcting systems
- gosub100 2y agocouldn't possibly be due to more planes flying more flights.
- piombisallow 2y agoThey haven't actually analyzed reported turbulence, it's just a simulation study: "Turbulence data from aircraft could also be analyzed, but the time period for which quantitative, automated measurements are available is far shorter than the 42 years covered here, making trend detection problematic."
- thfuran 2y agoNo, it just turns out that things get more energetic when you dump a lot of energy into a system.
- lxgr 2y agoOn the other hand, so far I haven't heard any reports of any steel mill or cement plant being destroyed by clear air turbulence.
- piombisallow 2y agoIs there anything global warming can't do?
- triceratops 2y agoConvince some people it exists. Whether it's responsible for more CAT - who knows?
- cassepipe 2y agoIt is according to the article
- deleted 2y ago[deleted]
- bromuro 2y agoI prefer to call it climate change, as it is a change of the conditions where everyone lives. As such, it is expected to affect everyone life.
- atlasy1 2y ago[dead]
- osipov 2y agoCommercial pilot here. Instead of climate change, we should be talking about continuous descent profiles (CDPs) that have become more common in the past years 5-10 years. These profiles with idle engines allow for a smoother, more fuel-efficient descent by reducing the need for level-off segments. However, CDPs can increase the perception of turbulence during descent. This is because aircraft remain at higher altitudes for longer periods, where atmospheric instability and wind shear are more pronounced. This increased turbulence is not due to climate change but rather the result of these optimized descent procedures aimed at reducing fuel consumption and minimizing environmental impact.
- vessenes 2y agoInteresting! I didn’t know that descent profiles had changed this decade. Now that you mention it, I seem to recall far less leveling off than when I was younger, at the very least you’ve incepted the idea into my head now. Also worth noting that to a passenger, CAT is the worst feeling you’ll have on most flights — the “oh shit we’re not flying anymore” vibe is real bad, and usually when you hit proper air again, the sudden jerk feels bad as well. As someone with like 8 flight hours to my name, I’ll say to a learning pilot, stalling feels much worse than CAT would, it’s a different sort of not flying, it’s like “oh shit the plane forgot how to fly, what now”.
- sandywaffles 2y ago> [Clear Air Turbulence] is particularly common around the tropopause, the boundary layer between the troposphere and the stratosphere, at altitudes between 7,000 and 12,000 meters (23,000 to 39,000 feet) . Oh, excellent the altitudes that 99% of aircraft fly at, unaffecting the ultra rich who fly private jets at 40,000k-50,000k+.
- hiatus 2y ago> Oh, excellent the altitudes that 99% of aircraft fly at, unaffecting the ultra rich who fly private jets at 40,000k-50,000k+. I didn't realize private jets fly so high. What's the reason for the difference in elevations?
- pc86 2y agoPrivate jets don't really fly at 50k that often but I'm sure there are some that can. 40-42k is pretty common though. There are a handful of reasons. In no particular order: 1) additional separation between recreational private flights and scheduled commercial flights 2) higher performance in small private jets with typically less than 1k lbs of people and cargo 3) winds are generally faster the higher you go so you'll usually go about at high as you're able, at least in one direction. Most private jets aren't someone flying a billionaire around in a $60M Gulfstream, they're $3M toys being flown around by the owner to go to their ski trip.
- nickjj 2y ago> 3) winds are generally faster the higher you go so you'll usually go about at high as you're able, at least in one direction. I recently flew from NYC to Lisbon, Portugal and it was 6.5 hours there (flying east) and 7.5 hours back (flying west) because you go with and against the jet stream. I wonder if there's a noticeable difference if you fly at a lower altitude against the wind. It didn't seem like the plane adjusted for that, it cruised at the same altitude both ways from what I remember. Both flights used the same exact plane type (A330neo).
- 2y ago
- w14 2y agoThis does not seem to be borne out by the accident statistics, which apparently show no trend in turbulence related accidents. (https://www.ntsb.gov/safety/safety-studies/Documents/SS2101.pdf https://www.ntsb.gov/safety/safety-studies/Documents/SS2101....) I don't know if there are other factors which might be masking a rise in incidence of CAT from accident stats?
- cassepipe 2y agoThe article seems to say that other than direct passenger injury, the issue is premature airframe fatigue, which I guess that if remarked on inspections, does not end up in the incident category.
- cpncrunch 2y agoAlso, they just looked at 2 years, so there could be cherry picking. Jet stream is affected by el nino. 1979 was weak el nino, 2020 was moderate la nina. https://ggweather.com/enso/oni.htm https://ggweather.com/enso/oni.htm
- dclowd9901 2y agoRight, and those two years are generationally distant. Another question I have is if pilots have a stable mechanism (that is, an unchanged objective sensor or something) that records the CAT or if it’s recorded by pilots, whose sensitivity to CAT might differ over time. Didn’t mention in the article how it’s measured.
- throwup238 2y agoCATs are recorded in pilot reports using terms like "light", "moderate", "severe", and "extreme" which each have a definition. I.e. severe is "Occupants are forced violently against seat belts or shoulder straps. Unsecured objects are tossed about. Food service and walking are impossible." I think only severe and extreme turbulence need mandatory reports and the lower two levels are a bit more subjective ("Food service and walking are difficult") Newer planes have sensors to measure eddy dissipation rates which are an objective measure of turbulence but I don't know how widespread those systems are and whether they get reported anywhere. They're mostly used for long distance transoceanic flights.
- Octabrain 2y agoI hate flying with passion and get extremely scared when flying through turbulences but, there was a journalist in my country, that also had experience as a pilot and said once on TV that during turbulences, is one of the safest moments in a plane. I don't remember the reasons but is there anybody in here with knowledge in the field that could confirm/deny this?
- mrWiz 2y agoDo you recall why they said it was the safest? My first guess is because the pilots are paying more attention while flying through turbulence.
- MichaelNolan 2y agoMy first guess is that during turbulence everyone has their seatbelt on. No one is walking around the cabin. It’s only at the start of unexpected turbulence that anyone should get hurt. Once your seatbelt is on things have to get pretty bad to get hurt.
- sandworm101 2y agoIt is safe because you are flying. Airplanes almost never have issues at altitude. Problems occur when closer to the ground. Landing/takeoff are the most dangerous times, the transitions between flying and not flying.
- FabHK 2y agoThe aviation industry has a perfect record, they've never left anyone up there.
- ibejoeb 2y agoThat's just not true. No turbulence is better than turbulence. That said, experiencing light chop on a modern large airplane presents no danger to the airframe or properly secured passengers. You really should be strapped in, though, especially if you're on a small plane. Wake turbulence, for example, actually does present a significant risk to smaller aircraft.
- bparsons 2y agoThere is also just a huge increase in global air travel, which should increase the number of total incidents. The number of commercial flights doubled between 2004 and 2019, and is expected to continue on that trend for some time.
- nashashmi 2y agoOne day we will research a boson particle that can be fired at the air and cause an abrupt polarization allowing for planes to travel through with very little air resistance.
- thisisauserid 2y agoI had never heard of Clear Air Turbulence until last month when I finally read the first Culture novel by Ian M. Banks: Consider Phlebas. Now I know that it's the perfect name for a space pirate ship.
- card_zero 2y agoChris Foss seemed to think along similar lines when he made Gillan's album cover. https://en.wikipedia.org/wiki/Clear_Air_Turbulence_(album) https://en.wikipedia.org/wiki/Clear_Air_Turbulence_(album)
- londons_explore 2y agoIf plane wings were hinged (allowing a wing to flop down, but not up), then even the worst turbulence couldn't cause negative G in the cabin. That would pretty much eliminate injuries. Obviously the wings need to lock into place for landing, and many structural elements of the craft would need to be redesigned.
- animex 2y agoCould this be internet-enabled flight bias? Now that we have more and more WiFi enabled flights, more people posting about it on socials...so public awareness grows but as indicated before only incident-related stats are being recorded. One can extrapolate if incidents including damage or injury are not increasing per capita of flights it's probably not a trend.
- jameshart 2y agoMost of the recent widely publicized CAT injuries have been on long distance flights between Europe and South Asia. One thing that’s happened in the past couple of years along that air corridor is the squeezing of flight paths out of Ukrainian, Russian, Israeli, and Afghan airspace. Planes taking more circuitous routes, giving them less options to avoid weather conditions, much of the flight over hot mountainous terrain… could be a contributing factor to increasing incidents of dangerous turbulence affecting flights, even if the conditions themselves haven’t become more common.
- therobots927 2y agoEdit: I just realized that the chart is increase of probability between 1979 and 2020, so to modify my comment I’ll just say that it wasn’t just that geographic region that saw an increase. It seemed to correlate with the jet streams Well the study in the link has a chart of some sort of duration weighted probability of CAT (which somehow ranges from 0 to 2.5 instead of 0 to 1?), which would correct for the total volume of flights because it’s a ratio. It’s more likely that the jet streams are getting more turbulent due to climate change.
- gerdesj 2y ago"Most of the recent widely publicized CAT injuries have been on long distance flights between Europe and South Asia." OK but you'll need a citation for your assertion and that is only about reported CAT via media sources and not what the article is on about - CAT events worldwide. The article invokes evidence across the entire planet and cites Prosser et al with 1979 vs 2020 graphics, evidence and discussion. It also concludes that jet streams are where CAT events are intensifying.
- jameshart 2y agoThe article exists because of several recent high profile CAT incidents. It cites data from several years ago (before the recent spate of stories) that only talks about increases in CAT-conducive conditions, but says nothing about increases in actual incidents. The article leaves maybe the impression that any recent spike in high profile turbulence events might be a result of the changes in jet stream activity but doesn’t actually provide much justification for that. Other posts on this thread point out that there was no actual increase in reported CAT encounters that correlates with the proposed mechanism so… unclear if the article’s data says much if anything about recent media-reported CAT events.
- diogenescynic 2y agoI can't tell if it's just me or something with flights but recently when I take flights I get an intense headache that isn't similar to other headaches.
- erixM 2y agoFor a few months, I used to have headaches too in the last 10 minutes before landing of every flight. Since I had a surgery for my sinusitis a few months before, I thought it was because of some air pressure buildup in my maxillary sinuses that wasn't returning to normal air pressure fast enough. Now every time I am close to landing I make sure the air circulates through both nasal cavities very well and I haven't had any problems anymore.
- diogenescynic 2y agoInteresting! I have been having issues with my sinuses. I wonder if that is the cause.
- therobots927 2y agoIs anyone aware of the feasibility of research into using LIDAR to detect CAT? This study from last October claims to have found a method for detecting CAT ahead of time with LIDAR: http://ui.adsabs.harvard.edu/abs/2023Photo..10.1185Z/abstract http://ui.adsabs.harvard.edu/abs/2023Photo..10.1185Z/abstrac... This type of technology would be incredible in my opinion, and I’m also of the opinion that increased turbulence (assuming it is actually increasing) could be easily tied to climate change and the recent warming of the pacific and Atlantic oceans due to regulations on sulfur in cargo ship fuel (but that’s a tangent to this topic)
- oron 2y agoShameless plug here. I work at SkyPath (https://skypath.io https://skypath.io) we monitor and collect CAT data from 1000's of flights in real time and predict CAT events with the help of an AI model. Pilots are extremely happy with our solution, we signed several of the major airlines in US and have active evaluation programs with several others.
- pc2slow4webpack 2y agoI see the site claims to save fuel, is this in the form of providing routing? I assume that patching data needs to get in to the autopilot system at some point, how does that work?
- oron 2y agoMore predictable routes and minimizing encounters with CAT can indeed help reduce fuel consumption while maintaining safety. This is a relatively small saving for each flight which can add up to a big chunk at the end of the year.
- HeatrayEnjoyer 2y agoSigned? What does authenticating have to do with it? Is there doubt about data providence?
- oron 2y agoSigned as in purchased a subscription for our service to provide data from their aircraft (using iPad sensors pilots are using) and get real time alerts and predictions regarding their flight and route.
- bozhark 2y agoEmbedded systems or tack-on? This seems like the internal accelerometer would be adequate?
- 1propionyl 2y agoThis seems like one of those topics that seems to be eliciting some response we might consider normal if it was code switched into Bay Area or NYC speak but seems to be getting a lot of pushback because it sounds like it's coming from particular airline boosters. This isn't to say either of those things really happen just it sometimes sure seems like it.